Edge Case
by usa123
Summary: When Steve suffers from heat stroke on a mission, Tony and Bruce make some modifications to his uniform. Based on a spoiler-free photo from the Cap 3 set. Absolutely no spoilers for AOU or Cap 3. No slash, no ships.


**(I apologize if anyone receives this notification more than once. Apparently some of you are unable to access this story with the current URL, so I tried reuploading the chapter. Thank you for your understanding!)**

 **A/N: To truly make this story spoiler-free, it's set between just before _Age of Ultron_. If you would like to see the picture in reference, it can be found with an awesome caption here: twitter dot com ****/clarkgregg/status/599308946784944128 .**

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When Steve Rogers opened his eyes, he found himself surrounded by unending whiteness. He blinked and, after fighting hard to pry his eyelids apart again, the world sharpened into focus. Soft beeping made its way into his consciousness a moment later and his addled brain was able to deduce that he was in a hospital room, though it was still too foggy to figure out why.

Cool air brushed across his chest and Steve quickly realized he was shirtless. Panic briefly shot through his system, waking his sluggish body enough for him to lift his head and see a pair of running shorts slung low on his hips. A thin white sheet covered him from the waist down, though it offered little protection against the frigid temperatures of the hospital room. As the momentary adrenaline began to subside, Steve quickly examined his body, finding an IV in the back of his right hand, but no visible bandages or casts. His burst of energy now spent, he laid his head back against the pillow, feeling no pain or discomfort anywhere on his person.

"You're awake," Steve slowly looked up to see Tony Stark standing in the doorway, dressed casually in a black T-shirt and jeans. There was a large gash over his brow held together with two butterfly bandages.

"Wha 'appen'd?" Steve croaked, his throat suddenly dry and scratchy.

Tony strode toward the bed and picked up a plastic cup from the side table. He pointed the bendy straw in Steve's direction and held the cup by the soldier's mouth. Steve reached out to hold the cup himself and was shocked to see his hand shaking.

"I'll hold it. You just drink," Tony instructed, readjusting the height of the glass. Steve was too thirsty to fight the inventor so he took a few long sips of the cold liquid and almost sighed in relief.

"Slow down tiger," Tony pulled the cup away slightly. "Don't make yourself sick. It's not going anywhere."

Steve nodded and forced himself to drink more slowly. "What happened?" he repeated, when the cup was almost empty.

"You passed out," Tony stated bluntly, refilling the cup from the plastic pitcher and offered it to Steve again. "Heat stroke."

"I did?" Steve questioned, staring up at his friend in confusion.

"You did the whole 'eyes rolling back into the head' bit and everything," Tony tried to sound nonchalant, but it was obvious he had been deeply concerned about his teammate. "Your core temp was one-twenty. You should have seen the team running around, trying to get you cooled down—you weren't even sweating at that point. Luckily Clint had already secured the 084 at that point or the mission would have been a total bust."

"Right. Arizona," the soldier managed, as he vaguely remembered a mission briefing about a highly volatile 084 in Phoenix. He tipped his head forward and sucked down the second glass of water.

"In the middle of July," Tony replied with a full-body shudder. "You want more?"

"No, I'm good f'r now," Steve rasped. "Thanks, though."

"Yup." Tony shoved the side table over Steve's bed and placed the cup and pitcher within the soldier's reach. "Your suit doesn't breathe," he stated as he dropped into a nearby plastic chair.

"What do you mean, 'doesn't breathe'?" Steve said, now fully awake. With a slightly trembling finger, he poked a button on the inside of the bed rail, which raised the headrest into a sitting position.

"Doesn't wick moisture away from your skin. It keeps all the sweat locked in there. Without any air flow, your body couldn't evaporate your sweat, which, as you know, is the body's way of cooling you down, and–"

"I passed out." Steve shifted uncomfortably. "Sorry."

"Nothing to be sorry about. If we had known you'd have super sweat, we could have done something about it. As is, Bruce and I already mocked up some new designs for your uniform." The inventor pulled his phone from his back pocket and flashed a hastily drawn sketch in Steve's direction. "We'll keep the same exterior for continuity, but we need to change up some of the materials so you don't pass out again."

Steve nodded slowly and was about to respond when a young nurse stepped into the room. "Steve Rogers?" he asked, without looking up from the tablet he was holding.

"There should be a 'Captain' in there somewhere," Tony informed the nurse, scooting away from the bed to allow him access to his patient. Steve made a thumbs-up gesture, indicating that he'd understood that reference, and Tony grinned.

"I know, I know," he announced to the nurse who was hurriedly making a note about Steve's rank in his records, "I have to leave while you examine him. Cap, one of our resident assassins will be here soon to sit with you so I can do some SI business this afternoon." He shuddered violently, his face contorting into an unpleasant expression. "The things I do for Pepper...Anyway, it'll take Bruce and I a few days to build a prototype, so when you get out of here, stop by the lab, see what you think about the new suit," he said before he flashed a peace sign and disappeared into the hallway.

* * *

Steve endured two days of seemingly endless tests to make sure his body hadn't suffered any harmful effects from the heat stroke before he was released from the helicarrier's med bay, on the promise that he would continue to take it easy for the next few days. True to his word, Steve took a two-hour nap and consumed thirty-two ounces of electrolyte-enhanced water before he biked over to Avengers' Tower.

"Good to see you on your feet," Bruce said warmly as Steve stepped into his and Tony's shared R&D lab. "You gave us quite the scare."

"I'm really am sorry about that," Steve replied, absently rubbing the back of his neck. "I've never been to a desert in peak heat so I didn't know what to expect."

"And now you do," Tony danced out of a small room with what looked like Steve's old uniform top on a hanger. "Well, whaddya think?"

Steve ran a careful eye over the uniform before hesitantly venturing, "Like you said, it looks the same."

Both Tony and Bruce smiled widely. "Excellent," Tony shoved the hanger at Steve. "Now go try it on."

Steve walked into the attached restroom and hung his uniform on the towel rack. After closing the door behind him, he slid the uniform top off the hanger and was surprised to see the shoulders drop a few inches.

"It's two pieces now," Tony called from behind the closed door.

"Yeah, I figured that out," he called loudly as he pulled off his T-shirt. Then, he tucked the sleeves into the body of the uniform and caught what was now the underlayer as it slid toward the ground.

"Is this some kind of a joke?" he asked as his eyes landed on the tightly-knit mesh squares set into the front and back of his uniform. They started at the end of his ribcage and spanned almost his entire abdomen, connected by only a few inches of thick fabric at his sides.

"Just try it on and we'll explain," Tony responded, almost gleefully.

Steve reluctantly pulled on the sleeved layer and exited the bathroom, holding the second layer, which now resembled a bulletproof vest, in one hand.

"I look like a Chippendale."

"Don't be silly—they wear far less." Tony took a slow walk around Steve, inspecting the look and the fit of the underlayer while he scrawled notes on his tablet. "How does it feel?" he asked when he was through.

"Kinda weird," Steve admitted, able to feel the air conditioning blowing directly onto his abs. "It doesn't seem like something you would normally design."

Tony and Bruce exchanged a quick glance and Steve nodded knowingly. "I'll make sure to give Edna a call when I get out of here."

"I don't know how she found out," Tony groused, handing the tablet to Bruce. "She was waiting outside the lab when I got back from visiting you. After calling me an idiot for not considering all the variables of your superness, she proceeded to school both me and Bruce on this mesh stuff. We ran with her idea and modified it so it's now a one-way barrier. See?" Tony pulled a pen from his pocket and stabbed Steve in the abdomen. The soldier instinctively braced himself, even though the pen would do him little harm, but felt only a slightly pressure as the mesh deflected the impact.

"It has similar properties to chain mail but has been micro-sized for your convenience," Tony explained. "Basically, it'll keep the bad stuff out, while allowing your body to regulate itself. There's a similar patch on your lower back too," Tony patted the said area before grabbing Steve's right arm and lifting it into the air. "The two under your arms are a little different. They're more reinforced because they're not covered by a second layer but they'll still offer some air flow."

"Let him try on the other piece," Bruce said as he finally looked up from the tablet. "See how they fit together."

After Tony released his arm, Steve quickly maneuvered his way into the outer vest. "It does feel better," he admitted, tugging it down to his hips. He did a few cautious twists and arm circles, then bent down and placed his palms flat on the ground. After a second, he swung his legs over his head and flipped upright. "Not as constricting."

"And just as strong," Tony added with a scowl at Steve's unreal athleticism. Quickly wiping the expression off his face, Tony reached over and tapped the uniform, just over Steve's heart. "There's also a sensor in there that monitors your body temperature. Before you ask, we put one in Barton's suit, Romanov's suit, Banner's pants—which might get awkward—" Tony flinched as Bruce fixed him with a scathing look. "And everyone else's suits," the inventor quickly finished, throwing up his hands on mock surrender. "They're all connected to JARVIS so he'll give us warning before something like this happens again."

"That sounds like a great idea," Steve said honestly.

"Well, it was ours—what did you expect?" Tony shot back, without any heat, but neither Bruce nor Steve were fooled. Both knew that Tony secretly reveled in his team's recognition and considered it proof that he was truly evolving from the uncaring playboy he'd used to be.

"There's a little caveat," Tony piped up, drumming his fingers against Steve's chest, "the sensors have to be individually calibrated. Because you run hotter than the rest of us mere mortals, you'll have to work out in your suit a few times, so JARVIS can determine your normal readings."

" _Not_ for at least another twelve hours," Bruce amended. "You need your rest, Steve."

"I'll come back tomorrow, then," Steve said with a wide smile. "Thanks for looking into this for me," he said as held out his hand to his teammates. "I really appreciate it, and I'm sure I speak for everyone else when I say they do too."

"Anytime, Steve," Bruce replied, heartily shaking the soldier's hand.

Then, Steve turned to face Tony, his hand still extended, but the inventor hesitated. "Steve, about the first suit—"

"Tony, it worked great for 99% of our missions," Steve interjected. From the moment he'd heard Tony recount how Edna had yelled at him for not considering all the variables, he'd known Stark might try to apologize. For better or worse, the woman always spoke her mind, without considering how her words might affect those she was truly trying to help. Everyone in Tony's inner circle knew he took great pride in his inventions and that he considered it a personal failure if they didn't work as designed, especially if their failure caused the injury of one of his teammates. It was a great responsibility to bear, so they all did their best to let Tony know that they appreciated all the modifications to their equipment, each in their own ways. "I didn't know I was going to react to the extreme heat like that and I absolutely believe that if you'd known, you'd have accounted for it, with a suit as great as the one you just designed."

Stark shifted his weight uncomfortably from foot to foot. "I have all the data in my files. I should have been able to put the pieces together," he muttered.

"Bull. It was an unforeseen...what did you call it when you were updating JARVIS' protocols?" Steve scrunched up his face in thought for a second, then snapped his fingers and pointed at Tony. "An edge case. It was an unforeseen edge case."

Bruce took this opportunity to elbow Tony in the side. "See?"

Obviously he had said something similar to Stark earlier because Tony made a face at his lab partner before turning back to Steve. "So you do listen when Bruce and I speak geek."

Steve shrugged but the smile he was desperately trying to hide gave away the answer.

After another moment, Tony nodded crisply and shook Steve's hand. "An edge case it shall be. Now, if you wouldn't mind exiting the lab, we've got more suits to modify."

Steve's grin widened on seeing the "old" Tony return and he quickly changed back into his T-shirt, leaving the uniform top hanging in the bathroom. "Be careful," he instructed as he exited the lab, even though he knew his request would fall on deaf ears.

Tony made a grunt of acknowledgement as he and Bruce huddled over the table filled with various parts from Sam Wilson's broken wings.

"JARVIS," Steve heard Tony command as the elevator doors slid closed, "cd into Falcon, make a new folder. Name it Mark II: The Inseparable Wing Update."

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 **Thanks for reading! I'd love to know what you thought.**

 **(Also, find me on Tumblr if you feel so inclined: usaOneTwoThree.)**


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